Everyday vs Every day

Everyday is an adjective. You can replace it with the adjective 'daily' or 'ordinary'.

Example: I always follow my everyday schedule. 

Every day is a phrase that can act like an adverb or a noun. You can replace it with 'each day'.

Examples: I wake up at seven every day.
                 Every day is important in student life.


So the difference between Everyday and Every day is that the single word term 'everyday' can be used only as an adjective before nouns. And the two-word term 'every day' can be used anywhere in a sentence as an adverbial phrase or a noun phrase.